Serial attached SCSI (SAS) is a computer bus that is used to move data to and from computer storage devices, such as hard drives and tape drives. SAS depends on point to point serial protocol. Typical serial attached SCSI systems include an initiator, which is a device that originates service and requests for processing by a target device and receives responses for these requests from the target devices. An initiator may comprise a controller or host device. Targets are devices containing logical units and target ports that receive device service and task management requests for processing, and send responses for the same requests to initiator devices. Target devices may comprise a hard disk or disk array. Expanders are devices that facilitate communication between the SAS devices and facilitate the connection of multiple SAS end devices. A phy is a physical link that connects an SAS device to another SAS device. A port is a collection of one or more phys.